High magnification projection lens

ABSTRACT

An inverse telephoto lens having ten elements, none in contact, is useful as a microfilm projection or camera lens, having a magnification ratio of 180:1 and numerical aperture of 0.42.

v r D United States Van Orden [541 HIGH MAGNIFICATION PROJECTION LENS [751 lnventor: Lynn L. Van Orden, Holley, N.Y. [73] Assignee: Bausch & Lomb Incorporated,

Rochester, NY.

[22] Filed: Sept. 5, 1972 [21] Appl. No.: 285,978

[52] US. Cl. 350/214 [51} Int. Cl. G02! 9/64 [58] Field of Search 350/214 1 Sept. 18, 1973 156] References Cited UNITED STATES PATENTS 3,656,839 4/1972 Trolls 350/214 Primary Examiner-John K. Corbin Attorney-Frank C. Parker et al.

[57 ABSTRACT An inverse telephoto lens having ten elements, none in contact, is useful as a microfilm projection or camera lens, having a magnification ratio of 180:1 and numerical aperture of 0.42.

5 Claims, 1 Drawing Figure HIGH MAGNIFICATION PROJECTION LENS BACKGROUND OF THE INVENTION The invention lies in the field of multiple component lenses. Generally similar prior designs appear in US. Pat. No. 3,656,839 and patents cited therein.

SUMMARY OF THE INVENTION The lens in question has elements in two main groups, one of which is positive and one which is negative. Its magnification is l80X and the numerical aperture is 0.42. All of the lenses are airspaced from one another.

The positive group is toward the short conjugate and has first a negative meniscus lens I concave toward the short conjugate. It is followed by a thick positive meniscus lens ll concave toward the short conjugate.

Next is a subgroup of three lenses, respectively a biconvex lens III, a biconcave lens IV and a biconvex lens V, and then a subgroup of two lenses, respectively a biconvex lens VI and a negative meniscus lens VII concave toward the short conjugate. All of said lenses together constitute a positive group and all are closely but distinctly airspaced from one another.

The next lens, which is the first lens of a negative group is spaced at least seven times the overall focal length away from said negative meniscus lens VII, and it is a negative meniscus lens VIII concave toward the short conjugate. The next lens is spaced almost two focal lengths away from lens VIII and it is a negative meniscus lens IX concave toward the short conjugate. It is closely spaced from a positive lens X with which the negative group is concluded. 7

It should be noted that the surfaces which define the spaces between lenses l and II and lenses IX and X are very nearly plano, and in particular designs such surfaces may be either of positive or negative radius, although their radii will always be of substantial absolute magnitude. The shape of the lenses defining such surfaces might therefore be described in different terms in two different examples of the same overall design. For example, a lens which is a negative meniscus in one design may become a plano-concave in the next design, or even a biconcave if the radius were to change sign. Those skilled in the art will therefore appreciate that the foregoing verbal lens description is subject to variations in phrasing to accommodate such shifts in sign for the long radii.

The lens is well corrected and it may be noted that the radii tend to be long and the surface curves therefore relatively shallow. Under these circumstances the corrections tend to be shared among the surfaces and the lens elements fabrication, assembly and alignment is greatly facilitated.

DESCRIPTION OF EMBODIMENTS The lens in question is subject to numerous variations in design, four of which are set forth, one in each column of the table below, where each element is described by the first order construction data, each radius R, thickness t, and space S, is subnumerated in increasing order from the short conjugate toward the long and is given as a ratio of the focal length f as unity. The glass types, subnumerated as above, are given in refractive indices m, and dispersion values v. Radii concave toward the short conjugate are treated in the table as negative. Radii l8 and 19 particularly are sometimes posi- 2 tive and sometimes negative. They are therefore given as positive and the values themselves are shown 33.66;. ative when the design so requires. Radii longer than 60f may be considered infinite and may be taken to include both positive and negative radii of such lengths.

-R. 2.516; 2.362; 2.491; 2.447; R, :60; :60; :60; :60; R, :60] :60; $601 :60; -11, 2.024; 2.020; 2.013; 2.013; R, 54.417; 54.292; 54.235; 54.242; -a. 3.007; 3.000; 2.997; 2.997; -12, 3.007; 3.000; 2.997; 2.997; R, 6.130; 6.116; 6.109; 6.110; R, 6.657; 6.641; 6.634; 6.635; R,., 6.000; 5.937; 5.930; 5.931; R" 5.519; 5.507; 5.501; 5.502; R,, 10.130; 10.156; 10.146; 10.147; -11 7.173; 7.116; 7.093; 7.141; R,, 22.045; 21.023; 21.322; 21.536; R,, 1.666; 1.674; 1.662; 1.673; -R.. 3.304; 3.467; 3.563; 3.700; R., 2.435; 2.602; 2.605; 2.557; R... --17.343; :60; 33.440; 27.28lf R... :60) 35.265; :60)" :60f -R... 4.753; 5.106; 5.093; 4.360; 1, .571; .569; .569; .569; 1, 1.479; 1.476; 1.474; 1.474; 1, .722; .721; .720; .720; 1. .309; .309; .303; .303; 1, .501; .500; .499; .499; 1. .523; .521; .521; .521; 1, .311; .310; .310; .310; 1. .231; .230; .230; .230; 1. .361; .360; .359; .360; 1,, .601; .600; .599; .599; s .019; .020; .020; .020; s, .014; .014; .014; .014; s, 065; .065; .065; .065; s. 136; .136; .135; .135; s, 019; .019; .013; .013; s. .073; .039; .039; .039; s, 7.126; 7.033; 7.127; 7.046; 5. 1.632; 1.754; 1.725; 1.754; s. 010; .010; .010; .010; n 1.620 1.620 1.620 1.620 n 1.620 1.620 1.620 1.620 1.720 1.720 1.720 1.720 n 1.691 1.691 1.691 1.691 n 1.691 1.691 1.691 1.691 11,, 1.720 1.720 1.720 1.720 n 1.691 1.691 1.691 1.691 n... 1.691 1.691 1.691 1.691 1.720 1.720 1.720 1.720 1.526 1.526 1.526 1.526 v. 60.2 60.2 60.2 60.2 v, 60.2 60.2 60.2 60.2 11,, 29.3 29.3 29.3 29.3 v, 54.3 54.3 54.3 54.3 v, 54.3 54.3 54.3 54.3 v, 29.3 29.3 29.3 29.3 v, 54.3 54.3 54.3 54.3 v, 54.3 54.3 54.3 54.3 v, 29.3 29.3 29.3 29.3 v... 60.0 60.0 60.0 -60.0

Those skilled in the art will appreciate that minor variation in the above values may nevertheless be compensated for by certain well known assembly and alignment techniques. In the case of variations in glass types, it is thought that useful lenses could be assembled from elements whose refractive indices were within .002 of the values shown below, or whose dispersion values were within :2 of those values.

Additionally, lenses failing to conform precisely to the above construction values may nevertheless be put to effective use in applications whose requirements are less stringent than those for which the lens is primarily intended.

I claim:

' 1. An inverted telephoto lens having 10 elements in two groups, none of said elements being in contact with one another, said elements having values of radii R which are negative when centered toward the short conjugate, thicknesses t and spaces S ratioed to the focal length f as unity, said elementscomprising glasses 

1. An inverted telephoto lens having 10 elements in two groups, none of said elements being in contact with one another, said elements having values of radii R which are negative when centered toward the short conjugate, thicknesses t and spaces S ratioed to the focal length f as unity, said elements comprising glasses of refractive indices nD and dispersions upsilon , all of said values being subnumerated in increasing order from the short conjugate toward the long, and said values lying within the ranges set forth in the table below: 2.362f -R1 2.516f -60f R2 + OR - 60f -60f R3 + OR - 60f 2.018f -R4 2.024f 54.235f R5 54.417f 2.997f -R6 3.007f 2.997f -R7 3.007f 6.109f R8 6.130f 6.634f R9 6.657f 5.5980f -R10 6.000f 5.501f R11 5.519f 10.146f -R12 10.180f 7.098f -R13 7.173f 21.023f -R14 22.045f 1.662f -R15 1.674f 3.467f -R16 3.804f 2.485f -R17 2.605f -17.343f R18 60f -60f R19 35.265f 4.753f -R20 5.106f 0.569f t1 0.571f 1.474f t2 1.479f 0.720f t3 0.722f 0.308f t4 0.309f 1.499f t5 0.501f 0.521f t6 0.523f 0.310f t7 0.311f 0.280f t8 0.281f 0.359f t9 0.361f 0.599f t10 0.601f 0.019f S1 0.020f 0.013f S2 0.014f 0.064f S3 0.065f 0.135f S4 0.136f 0.018f S5 0.019f 0.073f S6 0.089f 7.046f S7 7.127f 1.632f S8 1.754f 0.009f S9 0.010f 1.618 nD1 1.622 1.618 nD2 1.622 1.718 nD3 1.722 1.689 nD4 1.693 1.689 nD5 1.693 1.718 nD6 1.722 1.689 nD7 1.693 1.689 nD8 1.693 1.718 nD9 1.722 1.524 nD10 1.528 58.2 Nu 1 62.2 58.2 Nu 2 62.2 27.3 Nu 3 31.3 52.8 Nu 4 56.8 52.8 Nu 5 56.8 27.3 Nu 6 31.3 52.8 Nu 7 56.8 52.8 Nu 8 56.8 27.3 Nu 9 31.3 58.0 Nu 10 62.0
 2. The lens of claim 1 having substantially the construction data set forth in the table below: -R1 2.516f t1 0.571f R2 + or - 60f t2 1.479f R3 + or - 60f t3 0.722f -R4 2.024f t4 0.309f R5 54.417f t5 0.501f -R6 3.007f t6 0.523f -R7 3.007f t7 0.311f R8 6.130f T8 0.281f R9 6.657f t9 0.361f -R10 6.000f t10 0.601f R11 5.519f S1 0.019f -R12 10.180 S2 0.014f -R13 7.173f S3 0.065f -R14 22.045f S4 0.136f -R15 1.666f S5 0.019f -R16 3.804f S6 0.073f -R17 2.485f S7 7.126f R18 -17.343f S8 1.632f R19 + or - 60f S9 0.010f -R20 4.753f nD1 1.620 Nu 1 60.2 nD2 1.620 Nu 2 60.2 nD3 1.720 Nu 3 29.3 nD4 1.691 Nu 4 54.8 nD5 1.691 Nu 5 54.8 nD6 1.720 Nu 6 29.3 nD7 1.691 Nu 7 54.8 nD8 1.691 Nu 8 54.8 nD9 1.720 Nu 9 29.3 nD10 1.526 Nu 10 60.0
 3. The lens of claim 1 having substantially the construction data set forth in the table below: -R1 2.362f t1 0.569f R2 + or - 60f t2 1.476f R3 + or - 60f t3 0.721f -R4 2.020f t4 0.309f R5 54.292f t5 0.500f -R6 3.000f t6 0.521f -R7 3.000f t7 0.310f R8 6.116f t8 0.280f R9 6.641f t9 0.360f -R10 5.987f t10 0.600f R11 5.507f S1 0.020f -R12 10.156f S2 0.014f -R13 7.116f S3 0.065f -R14 21.023f S4 0.136f -R15 1.674f S5 0.019f -R15 3.467f S6 0.089f -R17 2.602f S7 7.083f R18 + or - 60f S8 1.754f R19 35.265f S9 0.010f -R20 5.106f nD1 1.620 Nu 1 60.2 nD2 1.620 Nu 2 60.2 nD3 1.720 Nu 3 29.3 nD4 1.691 Nu 4 54.8 nD5 1.691 Nu 5 54.8 nD6 1.720 Nu 6 29.3 nD7 1.691 Nu 7 54.8 nD8 1.691 Nu 8 54.8 nD9 1.720 Nu 9 29.3 nD10 1.526 Nu 10 60.0
 4. The lens of claim 1 having substantially the construction data set forth in the table below: -R1 2.491f t1 0.569f R2 + or - 60f t2 1.474f R3 + or - 60f t3 0.720f -R4 2.018f t4 0.308f R5 54.235f t5 0.499f -R6 2.997f t6 0.521f -R7 2.997f t7 0.310f R8 6.109f t8 0.280f R9 6.634f t9 0.359f -R10 5.980f t10 0.599f R11 5.501f S1 0.020f -R12 10.146f S2 0.014f -R13 7.098f S3 0.065f -R14 21.882f S4 0.135f -R15 1.662f S5 0.018f -R16 3.563f S6 0.089f -R17 2.605f S7 7.127f R18 -33.440f S8 1.725f R19 + or - 60f S9 0.010f -R20 5.093f nD1 1.620 Nu 1 60.2 nD2 1.620 Nu 2 60.2 nD3 1.720 Nu 3 29.3 nD4 1.691 Nu 4 54.8 nD5 1.691 Nu 5 54.8 nD6 1.720 Nu 6 29.3 nD7 1.691 Nu 7 54.8 nD8 1.691 Nu 8 54.8 nD9 1.720 Nu 9 29.3 nD10 1.526 Nu 10 60.0
 5. The lens of claim 1 having substantially the construction data set forth in the table below: -R1 2.447f t1 0.569f R2 + or - 60f t2 1.474f R3 + or - 60f t3 0.720f -R4 2.018f t4 0.308f R5 54.242f t5 0.499f R6 2.997f t6 0.521f -R7 2.997f t7 0.310f R8 6.110f t8 0.280f R9 6.635f t9 0.360f -R10 5.981f t10 0.599f R11 5.502f S1 0.020f -R12 10.147f S2 0.014f -R13 7.141f S3 0.065f -R14 21.536f S4 0.135f -R15 1.673f S5 0.018f -R16 3.700f S6 0.089f -R17 2.557f S7 7.046f R18 -27.281f S8 1.754f R19 + or - 60f S9 0.010f -R20 4.860f nD1 1.620 Nu 1 60.2 nD2 1.620 Nu 2 60.2 nD3 1.720 Nu 3 29.3 nD4 1.691 Nu 4 54.8 nD5 1.691 Nu 5 54.8 nD6 1.720 Nu 6 29.3 nD7 1.691 Nu 7 54.8 nD8 1.691 Nu 8 54.8 nD9 1.720 Nu 9 29.3 nD10 1.526 Nu 10 60.0 